In order to play back audio signal with good quality, it is generally necessary to process the audio signal. For example, the audio signal may be processed according to the characteristics or parameters of the target playback device. Such processing is referred as device specific or centric audio signal processing. In general, the device specific audio signal processing involves anything related to presentation and calibration according to the playback device and/or environment. Typically the device specific audio signal processing may include equalizer processing, regulator processing, peak limiting processing, and so forth. As an example, if the playback device has a limited capacity of reproducing the high frequency component of the audio signal, then the audio signal can be processed to suppress the high frequency component accordingly to avoid any clicks, distortions or any other audible artifacts in the playback. Of course, it would be appreciated that the audio signals may be processed for any other purposes.
For some cases such as VoIP (Voice over Internet Protocol) communications and gaming, latency of the audio signal processing is a significant factor. Long latency of the audio signal processing is very likely to decrease the overall performance of the application and has negative impact on user experience. However, at present, solutions for audio signal processing usually cannot minimize the latency due to the consideration of fidelity. More specifically, the audio signal processing generally comprises transforms between time domain and frequency domain. For example, the audio signal may be transformed from the time domain to the frequency domain to obtain a series of frequency coefficients. The frequency coefficients can be modified according to the characteristics of the playback device. Then the audio signal with the modified coefficients is transformed back to the time domain for playback. There is a tradeoff between audio processing latency and computational efficiency. To achieve high resolution in the filter's frequency response, known approaches have to operate with high computational cost or significant latency. Moreover, in order to allow a fine level control of all frequency parameters, existing solutions usually introduce higher distortion or longer latency. However, in some audio processing such as device specific audio processing, it is only necessary to modify the band energy of a small number of bands to meet the quality requirement of most users.
In view of the foregoing, there is a need in the art for a solution for audio signal processing with low latency.